Prostacyclin

186.84 Ų [M-H]- [CCS Type: DT; Method: single field calibrated with Agilent tune mix (Agilent)]

196.67 Ų [M+Na]+ [CCS Type: DT; Method: stepped-field]

191.9 Ų [M-H]-

B01AC09

B - Blood and blood forming organs

QB - Blood and blood forming organs

Epoprostenol has two major pharmacological actions: (1) direct vasodilation of pulmonary and systemic arterial vascular beds, and (2) inhibition of platelet aggregation. In animals, the vasodilatory effects reduce right and left ventricular afterload and increase cardiac output and stroke volume. The effect of epoprostenol on heart rate in animals varies with dose. At low doses, there is vagally mediated brudycardia, but at higher doses, epoprostenol causes reflex tachycardia in response to direct vasodilation and hypotension. No major effects on cardiac conduction have been observed. Additional pharmacologic effects of epoprostenol in animals include bronchodilation, inhibition of gastric acid secretion, and decreased gastric emptying. No available chemical assay is sufficiently sensitive and specific to assess the in vivo human pharmacokinetics of epoprostenol.

Prostaglandins are present in most body tissues and fluids and mediate many biological functions. Epoprostenol (PGI2) is a member of the family of prostaglandins that is derived from arachidonic acid. The major pharmacological actions of epoprostenol is ultimately inhibition of platelet aggregation. Prostacycline (PGI2) from endothelial cells activate G protein-coupled receptors on platelets and endothelial cells. This activation causes adenylate cyclase to produce cyclic AMP which inhibits further platelet activation and activates protein kinase A. Cyclic AMP also prevents coagulation by preventing an increase in intracellular calcium from thromboxane A2 binding. PKA then continues the cascade by phosphorylating and inhibiting myosin light-chain kinase which leads to smooth muscle relaxation and vasodilation. Notably, PGI2 and TXA2 work as physiological antagonists.